xref: /kernel/linux/linux-5.10/net/sched/act_gact.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/act_gact.c		Generic actions
4 *
5 * copyright 	Jamal Hadi Salim (2002-4)
6 */
7
8#include <linux/types.h>
9#include <linux/kernel.h>
10#include <linux/string.h>
11#include <linux/errno.h>
12#include <linux/skbuff.h>
13#include <linux/rtnetlink.h>
14#include <linux/module.h>
15#include <linux/init.h>
16#include <net/netlink.h>
17#include <net/pkt_sched.h>
18#include <net/pkt_cls.h>
19#include <linux/tc_act/tc_gact.h>
20#include <net/tc_act/tc_gact.h>
21
22static unsigned int gact_net_id;
23static struct tc_action_ops act_gact_ops;
24
25#ifdef CONFIG_GACT_PROB
26static int gact_net_rand(struct tcf_gact *gact)
27{
28	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
29	if (prandom_u32() % gact->tcfg_pval)
30		return gact->tcf_action;
31	return gact->tcfg_paction;
32}
33
34static int gact_determ(struct tcf_gact *gact)
35{
36	u32 pack = atomic_inc_return(&gact->packets);
37
38	smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
39	if (pack % gact->tcfg_pval)
40		return gact->tcf_action;
41	return gact->tcfg_paction;
42}
43
44typedef int (*g_rand)(struct tcf_gact *gact);
45static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
46#endif /* CONFIG_GACT_PROB */
47
48static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
49	[TCA_GACT_PARMS]	= { .len = sizeof(struct tc_gact) },
50	[TCA_GACT_PROB]		= { .len = sizeof(struct tc_gact_p) },
51};
52
53static int tcf_gact_init(struct net *net, struct nlattr *nla,
54			 struct nlattr *est, struct tc_action **a,
55			 int ovr, int bind, bool rtnl_held,
56			 struct tcf_proto *tp, u32 flags,
57			 struct netlink_ext_ack *extack)
58{
59	struct tc_action_net *tn = net_generic(net, gact_net_id);
60	struct nlattr *tb[TCA_GACT_MAX + 1];
61	struct tcf_chain *goto_ch = NULL;
62	struct tc_gact *parm;
63	struct tcf_gact *gact;
64	int ret = 0;
65	u32 index;
66	int err;
67#ifdef CONFIG_GACT_PROB
68	struct tc_gact_p *p_parm = NULL;
69#endif
70
71	if (nla == NULL)
72		return -EINVAL;
73
74	err = nla_parse_nested_deprecated(tb, TCA_GACT_MAX, nla, gact_policy,
75					  NULL);
76	if (err < 0)
77		return err;
78
79	if (tb[TCA_GACT_PARMS] == NULL)
80		return -EINVAL;
81	parm = nla_data(tb[TCA_GACT_PARMS]);
82	index = parm->index;
83
84#ifndef CONFIG_GACT_PROB
85	if (tb[TCA_GACT_PROB] != NULL)
86		return -EOPNOTSUPP;
87#else
88	if (tb[TCA_GACT_PROB]) {
89		p_parm = nla_data(tb[TCA_GACT_PROB]);
90		if (p_parm->ptype >= MAX_RAND)
91			return -EINVAL;
92		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
93			NL_SET_ERR_MSG(extack,
94				       "goto chain not allowed on fallback");
95			return -EINVAL;
96		}
97	}
98#endif
99
100	err = tcf_idr_check_alloc(tn, &index, a, bind);
101	if (!err) {
102		ret = tcf_idr_create_from_flags(tn, index, est, a,
103						&act_gact_ops, bind, flags);
104		if (ret) {
105			tcf_idr_cleanup(tn, index);
106			return ret;
107		}
108		ret = ACT_P_CREATED;
109	} else if (err > 0) {
110		if (bind)/* dont override defaults */
111			return 0;
112		if (!ovr) {
113			tcf_idr_release(*a, bind);
114			return -EEXIST;
115		}
116	} else {
117		return err;
118	}
119
120	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
121	if (err < 0)
122		goto release_idr;
123	gact = to_gact(*a);
124
125	spin_lock_bh(&gact->tcf_lock);
126	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
127#ifdef CONFIG_GACT_PROB
128	if (p_parm) {
129		gact->tcfg_paction = p_parm->paction;
130		gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
131		/* Make sure tcfg_pval is written before tcfg_ptype
132		 * coupled with smp_rmb() in gact_net_rand() & gact_determ()
133		 */
134		smp_wmb();
135		gact->tcfg_ptype   = p_parm->ptype;
136	}
137#endif
138	spin_unlock_bh(&gact->tcf_lock);
139
140	if (goto_ch)
141		tcf_chain_put_by_act(goto_ch);
142
143	return ret;
144release_idr:
145	tcf_idr_release(*a, bind);
146	return err;
147}
148
149static int tcf_gact_act(struct sk_buff *skb, const struct tc_action *a,
150			struct tcf_result *res)
151{
152	struct tcf_gact *gact = to_gact(a);
153	int action = READ_ONCE(gact->tcf_action);
154
155#ifdef CONFIG_GACT_PROB
156	{
157	u32 ptype = READ_ONCE(gact->tcfg_ptype);
158
159	if (ptype)
160		action = gact_rand[ptype](gact);
161	}
162#endif
163	tcf_action_update_bstats(&gact->common, skb);
164	if (action == TC_ACT_SHOT)
165		tcf_action_inc_drop_qstats(&gact->common);
166
167	tcf_lastuse_update(&gact->tcf_tm);
168
169	return action;
170}
171
172static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u64 packets,
173				  u64 drops, u64 lastuse, bool hw)
174{
175	struct tcf_gact *gact = to_gact(a);
176	int action = READ_ONCE(gact->tcf_action);
177	struct tcf_t *tm = &gact->tcf_tm;
178
179	tcf_action_update_stats(a, bytes, packets,
180				action == TC_ACT_SHOT ? packets : drops, hw);
181	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
182}
183
184static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
185			 int bind, int ref)
186{
187	unsigned char *b = skb_tail_pointer(skb);
188	struct tcf_gact *gact = to_gact(a);
189	struct tc_gact opt = {
190		.index   = gact->tcf_index,
191		.refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
192		.bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
193	};
194	struct tcf_t t;
195
196	spin_lock_bh(&gact->tcf_lock);
197	opt.action = gact->tcf_action;
198	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
199		goto nla_put_failure;
200#ifdef CONFIG_GACT_PROB
201	if (gact->tcfg_ptype) {
202		struct tc_gact_p p_opt = {
203			.paction = gact->tcfg_paction,
204			.pval    = gact->tcfg_pval,
205			.ptype   = gact->tcfg_ptype,
206		};
207
208		if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
209			goto nla_put_failure;
210	}
211#endif
212	tcf_tm_dump(&t, &gact->tcf_tm);
213	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
214		goto nla_put_failure;
215	spin_unlock_bh(&gact->tcf_lock);
216
217	return skb->len;
218
219nla_put_failure:
220	spin_unlock_bh(&gact->tcf_lock);
221	nlmsg_trim(skb, b);
222	return -1;
223}
224
225static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
226			   struct netlink_callback *cb, int type,
227			   const struct tc_action_ops *ops,
228			   struct netlink_ext_ack *extack)
229{
230	struct tc_action_net *tn = net_generic(net, gact_net_id);
231
232	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
233}
234
235static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
236{
237	struct tc_action_net *tn = net_generic(net, gact_net_id);
238
239	return tcf_idr_search(tn, a, index);
240}
241
242static size_t tcf_gact_get_fill_size(const struct tc_action *act)
243{
244	size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
245
246#ifdef CONFIG_GACT_PROB
247	if (to_gact(act)->tcfg_ptype)
248		/* TCA_GACT_PROB */
249		sz += nla_total_size(sizeof(struct tc_gact_p));
250#endif
251
252	return sz;
253}
254
255static struct tc_action_ops act_gact_ops = {
256	.kind		=	"gact",
257	.id		=	TCA_ID_GACT,
258	.owner		=	THIS_MODULE,
259	.act		=	tcf_gact_act,
260	.stats_update	=	tcf_gact_stats_update,
261	.dump		=	tcf_gact_dump,
262	.init		=	tcf_gact_init,
263	.walk		=	tcf_gact_walker,
264	.lookup		=	tcf_gact_search,
265	.get_fill_size	=	tcf_gact_get_fill_size,
266	.size		=	sizeof(struct tcf_gact),
267};
268
269static __net_init int gact_init_net(struct net *net)
270{
271	struct tc_action_net *tn = net_generic(net, gact_net_id);
272
273	return tc_action_net_init(net, tn, &act_gact_ops);
274}
275
276static void __net_exit gact_exit_net(struct list_head *net_list)
277{
278	tc_action_net_exit(net_list, gact_net_id);
279}
280
281static struct pernet_operations gact_net_ops = {
282	.init = gact_init_net,
283	.exit_batch = gact_exit_net,
284	.id   = &gact_net_id,
285	.size = sizeof(struct tc_action_net),
286};
287
288MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
289MODULE_DESCRIPTION("Generic Classifier actions");
290MODULE_LICENSE("GPL");
291
292static int __init gact_init_module(void)
293{
294#ifdef CONFIG_GACT_PROB
295	pr_info("GACT probability on\n");
296#else
297	pr_info("GACT probability NOT on\n");
298#endif
299
300	return tcf_register_action(&act_gact_ops, &gact_net_ops);
301}
302
303static void __exit gact_cleanup_module(void)
304{
305	tcf_unregister_action(&act_gact_ops, &gact_net_ops);
306}
307
308module_init(gact_init_module);
309module_exit(gact_cleanup_module);
310